Range-finder for photographic cameras.



PATENTED JUNE 2, 1903.

A. L. LEWIS.

RANGE FINDER FOR PHOTOG'RAPHIG CAMERAS.

APPLICATION FILED MAR. 28, 1903.

N0 MODEL.

UNITED STATES Patented June 2, 1903.'

ATENT rerun,

ATWOOD LLOYD LEWIS, OF PHILADELPHIA, PENNSYLVANIA. I

SPEQKFICATIQN forming part of Letters Patent N 0. 729,948, dated June 2,1903.

Application filed March 28, 1908. Serial No. 149,928. (No model:

To aZZ whom it may concern:

Be it known that I, Arwoon LLoYDLEwIs, a citizen of the United States,residing at the city of Philadelphia, in the county of Philadelphiaand'State of Pennsylvania, have invented certain new and usefulImprovements in Range-Finders for Photographic Cameras, of which thefollowing is a specification.

My invention has relation to a range-finder for photographic cameras,and in such connection it relates to the construction and arrangement ofsuch a finder whereby the distance from the camera of an object ofpredetermined height may be measured directly upon the image-plate ofthe finder and the measurement thereafter transferred to thefocusing-gage.

The principal object of myinvention is to provide in a photographiccamera having a variable focus a finder having applied to theground-glass or image plate of the finder a scale so graduated that thedistance from the camera of an object of predetermined height will beindicated in the finder and the measurement so obtained can be readilytransferred to the focus-finding scale.

The nature and scope of my invention will be more fully understood fromthe following description, taken in connection with the accompanyingdrawings, forming part hereof, in which- Figure 1 is a side elevationalview of a photographic camera of a well-known type having afocus-finding scale and a range-finder embodying main features of myinvention. Fig. 2 is a perspective view, enlarged, of the graduatedplate to be applied to the rangefinder. Fig. 3 is a cross-sectional viewof Fig. 2; and Fig. 4. is a sectional view of the finder, taken at rightangles to the section illustrated in Fig. 3.

Referring to the drawings, a represents a camera of any well-known type,the camera illustrated being known in the trade as a No. 4 bulls-eyekodak. The camera a has mechanism (not shown) for varying the focus,which variation is indicated upon a scale I) by means of a shiftingpointer b, attached to the mechanism.

Into the opening of the finder cl is fitted a plate (1, of transparentor translucent material, having a scale (Z graduated as hereinafterdescribed. The plate d is fitted, preferably, as shown, in a box d ofmetal, being supported therein by offsets or prongs d and d projectingfromjthe side and end Walls, respectively, of the box (Z The box (1 hastwo flaps d by means of which the box may be readily inserted in orwithdrawn from the opening of the finder (Z.

The measurements or scale (1 upon the plate d are found as follows: Anobject of predetermined height-say six feetwhen viewed from a distanceof ten feet away will project upon the image-plate of the finder animage extending from that margin of the plate d which is below the 100mark upward to the mark numbered 10 on the scale.

'When the sameobject is fifteen, twenty-five,

fifty, or one hundred feet from the camera, its image will extend on thescale from said margin upward to the 15, 25, 50, or 100 mark, as thecase maybe. When the scale d has been once determined, as above setforth, all that is necessary to find the distance of any other objectsfrom the camera and to focus for that distance is to select in thepicture to be photographed an object which is known to be six feet highor of approximately that height and ascertain from the image of thatparticular object upon the scale d of the plate (1 the distance of theobject away from the camera. This measurement can then be used to setthe focus of the camera by moving the pointer I) over the focusing-scaleb to the corresponding distancemark. 7

It should be understood that where the plate (1 is carried by a box (1said box d may vary in shape and form, so asto fit varying shapes andforms of finder-openings used in the various types of cameras in whichthe focus is variable. The scale (1 while preferably used for an objectof predetermined height, may likewise be used for objects of 5 multiplethe height or of fractional height of the original object. Thus if thescale d was formed for the measurement of an object six feet high itcould be used for objects three feet high or twelve feet high by simplyin the firstinstance doubling the length of the image upon the scale (1or in the second instance halving'the length of said image.

Having thus described the nature and object of my invention, What Iclaim as new, and desire to secure by Letters Patent, is

1. In :a camera having a variable focus and provided with focusingmechanism and a scale therefor, a finder having uponits image-plate ascale, the measurements whereof are graduated so as to indicate thedistance of an object of predetermined height away from .the camera.

2. In a camera of the variable-focus type and provided with a focusingmechanism, a scale therefor and a finder, a scale-plate arrangedeto litthe opening above the imageplate of; the finder aud a scaleiformedonsaid scale;plate and having its measurements graduated to indicate thedistance from the 7 ATIVOOD LLOYD LEYVIS WVitnesses:

J. WALTER DoUGLAss, THOMAS M. SMITH.

